1. Field of the Invention
This invention relates to a lock-fastener for bags, briefcases or other receptacles adapted to be closed by a flap or cover thereon.
2. Prior Art
Most conventional lock fasteners basically comprise a female or socket member attached to the body of a bag and a male or plug member attached to flap and engageable with the socket member to close the flap over the bag. Inadvertently applied pressure to this type of lock fastener would sometimes cause separation of the plug member from the socket member, leading to an opened flap. Conversely, intended pressure to open the bag would often fail to unlock the fastener in the case where the bag is flat that is; not enough loaded, at might be experienced with lock fasteners of the type disclosed in Japanese Laid-Open Utility Model Publication No. 50-102706. To eliminate or alleviate such malfunctioning of the known devices, there have been introduced some improvements such as are taught in Japanese Patent Publication No. 61-25382 in which there is shown a lock fastener comprising a socket member having a guide chamber, a slide member movably supported in the chamber and having a retaining lug, and a plug member having an engaging tongue with an aperture dimensioned to receive the lug and adapted to move together with the slide member into and out of the chamber of the socket member. In this case, both hands of the user are required to register the aperture with the lug and thus join the engaging tongue with the slide member, which is literally tedious and time consuming. Another difficulty is that the engaging tongue can not make its way smoothly into and through the guide chamber of the socket member if the bag is loaded either too lightly or too heavily.